Apparatus for finishing tubular articles



April 21, 1942. G, w, BINNs ETAL.

APPARATUS FOR FINIHING TUBULAR ARTICLES Filed Feb. 2.8, 1939 2Sheets-Sheet l R5. Ns d THELER ATTORNEY.

April 21, 1942. G, w. BINNS ETA;

APPARATUS FOR FINISHING TUBULAP` ARTICLES Filed Feb. 28, 1939 2Sheets-Sheet 2 ATTORNEY.

Patented Apr. 2l, 1942 para TTES

APPARATUS FOR FINISHING TUBULAR ARTICLES of Ohio Application February28, 1939, Serial No. 258,986

6 Claims.

This invention relates to improvements in a method of and apparatus forfinishing tubular articles and relates particularly to the accurateformation or surfacing of thin-walled flexible sleeves or similarstructures, being particularly adapted for use in the grinding orfinishing of metallic cylinder liners for internal combustion engines.

One of the principal objects of the present invention is the provisionof an improved method of supporting a flexible walled article, eitherinteriorly or exteriorly in such manner as to maintain the same in itsnormal uniiexed condition by multiple application of either internal orexternal pressure thereto in a manner to lock the same againstdeformation from oppositely applied pressure incident to a machining orfinishing operation.

A further object of the invention is the provision of improved apparatusfor effecting multiple longitudinal and circumferential positionmaintenance of a flexible walled article with suitable resistance todeformation thereof during performance of a surfacing operation on theunsupported surface thereof. x

A further object of the invention is the provision of an apparatus ofthis character permitting ready positioning of the Work while positivelymaintaining the same against accidental dis placement during machiningthereof.

Other objects and advantages of the present invention should be readilyapparent by reference to the following specification, considered inconjunction With the accompanying drawings forming a, part thereof andit is to be understood that any modications may be made in the exactstructural details there shown and described, within the scope of theappended claims, without departing from or exceeding the spirit of theinvention.

Figure l is a fragmentary View of a centerless grinder in which a Workpiece is being mshed in accordance with the present invention.

Figure 2 is a fragmentary plan view of the parts illustrated in Figure1.

Figure 3 is a View partly in elevation and partly in section of a workpiece suported for machining in accordance with the practice of thepresent invention.

Figure 4 is a view looking to the right hand end of the constructionshown in Figure 3.

Figure 5 is a fragmentary longitudinal sectional View of the inventionas utilized in interior support of an article to be finished.

Figure 6 is a similar view illustrating the external supporting of anarticle for operation on the interior thereof.

Figure 7 is a sectional view as on the line l-l of Figure 5.

Figure 8 is a fragmentary sectional View illustrating a modified form ofsupporting means.

fifi

Figure 9 is a sectional view as on the line 9 9 of Figure 8, and

Figure 10 is a fragmentary View illustrating the application of aterminal protective device to the work holder.

In the drawings in which similar characters of reference are employedtodenote similar or corresponding parts throughout the several views,the numeral lil designates the bed of a centerless grinder having theopposed grinding Wheel Il and regulating wheel l2 intended jointly toengage a cylindrical Work piece I3 supported between the Wheels as byconventional Work rest blade lll.

An end stop l5 carried by the bed I0 serves to limit the axial movementof the work within the grinding throat.

Prior to the present invention extreme difficulty has been experiencedin attempting to produce the necessary concentric truly roundcylindrical surfaces on thin, flexible-walled sleeves such as areemployed, for example, in lining the cylinders of internal combustionengines. This has been due to the fact that the flexibility of theseWalls is such that they are bent and distorted even on the applicationof light pressure in the performance of surfacing or similar operationsand no satisfactory method has hitherto been found by which the same,even though initially formed to substantially proper cylindrical shape,could be held in this shape without distortion for nishing of a firstsurface thereon.

It is, of course, understood that after either the exterior or theinterior have been finished truly circular in cross section that theycan then be fitted within a chuck or mounted upon an arbor forproduction of the second surface.

The previous difficulty has been in the producing of the first surfaceWithout reproduction on the surface being finished of any irregularitiesexisting on the surface employed for holding purposes, due to thedistortion eiectible by such irregularities.

In accordance with the present method, hoW- ever, there has beenprovided a chuck or holding member which, in its dierent forms, may beapplied either interiorly to or exteriorly of `the article and isprovided with a multiplicity of yieldable work engaging devicesindividually actuated by light pressure insufficient to cause individualdistortions of the article, but on the contrary, conforming respectivelyto the irregularities thereof.

One embodiment of the improved holding member and its manner of use isillustrated in detail in Figures 3 to 7 of the drawings. As there shown,it comprises a body portion which, for convenience of manufacture, maybe formed from a series of similar bushings or collars IB, prefer n ablyprovided with interlocking portions such as the terminal flanges Ilreceived in the interior recesses or sockets I 8 for building up of asectional the springs 23 react.

tubular member designated as an entirety by the numeral I9.

Each of said sections I6 has formed therein a multiplicity of sockets 20extending in a general axial direction with respect to the collar I6 butat a slight angle such that the outer portions break through theperiphery of the collar in the elongated slots 2 I The exact anglebetween the axes of these sockets and the axis of the collar itself maybe Varied, but preferably is such as to constitute a sticking taper witha coeicient of friction,v such as to maintain the pressure devices, suchas the balls 22, against axial displacement on application of radialpressure thereto as respects the axis of the collar I6.

It is to be noted that the pressure members 22 may be inserted at therear or inner open ends of the sockets 2U and are individually backed upby yielding pressure means which may be of hydraulic or other characterbut for convenience of illustration have been indicated as compressionsprings 23. Intertting assembly of the adjacent collars causes onecollar to form a closure for the inner open ends of the sockets, eachsucceeding socket thus providing an abutment against which Suitablemeans are provided for securing the several sections together as aunit-in Figures 3 to 5, these means having been shown as a pair of discs24 and 25 centrally connected as by bolt 26 having nut 2'I to draw theparts together with suitable and adequate retaining pressure.

In the use of this device in connection with the finishing of tubulararticles, the thin-Walled sleeve or like article I3 is axially slid overthe member I9. The resistance of the individual springs 23 or theirequivalent is sufliciently light to permit of concomitant longitudinaland inward movement of the series of pressure members 22 in theirrespective sockets so that the sleeve may be readily pressed intoposition, being brought up, for example, against the limiting end stop28 carried by the disc 25,

When in this position, the work piece, as indicated in Figure 3, islongitudinally and circumferentially supported at a multiplicity ofpoints by the members 22, each individually, resiliently, outwardlyurged by an equal pressure so that the internal pressures correspond atall points; exist throughout the entire circumference of the article atbut slightly spaced points and therefore have no tendency to distort orVary the shape of the article.

At the same time, due to the slight angle of the slots, the members 22themselves will be substantially locked in position against radialmovement with respect to the supporting body I9 and/or thecircumscribing work piece I3 and will resist any tendency to distortionof the work piece by lateral pressure thereagainst at circumferentiallyspaced points.

It will thus be seen that the article is properly, satisfactorilysupported in its initial shape or form Without distortion and can thusbe inserted, together with the support I9, in the throat of a suitablemachine tool in a suitable tooling position, such as a centerlessgrinder, for example, where it may be rotated on its periphery-restingon the work rest I4 under rotational and pressure control of theregulating wheel I2 while a tooling or nishing operation is performedthereon by the grinding wheel I I. It is, of course, understood that inthe performance of this tooling operation the pressure reacting againstthe outer periphery of the Work is suitably controlled either manuallyby the operator or by interposition of resilient mechanism in themachine tool adjusting mechanism, such that the aggregate exteriorpressure on the work is maintained below a point which will causedisplacement of the frictionally locked, yieldingly urged members 22.

Upon completion of the tooling operation the unit as an entirety isremovedthe end stop retracted and the work piece progressively advancedaxially with respect to the member I9, as indicated in Figure 5-theretaining members 22 yielding to permit of ready slipping off of thearticle,

An alternative form of construction, similar in general respects to thatjust described but adapted for exterior engagement with articles whichare to be interiorly finished, is shown in Figure 6 where the sectionsIlia. have the similar sockets 29a, the pressure members 22a actuated bythe springs 23a. The essential difference in this form of constructionis that the sockets 20a extend inwardly and break through the inner faceof the members Ia and the telescoping or interiitting portions 29 and 39of the collars have interengaged threads so that the sections may bescrewed together to form a complete unit of desired length according tothe linear dimension of the work piece to be supported thereby.

The work piece, as before, is introduced in a direction tending tocompress members 22a against their backing springs, and retracted orwithdrawn by a continuance of the same movement.

In Figures 8 and 9 there has been illustrated a modied form of theinvention in which use is made of a multiplicity of resilient spiders,each having a hub portion 3| mounted on the centering stud 32 and heldin suitably spaced relation with respect to each other by the collars orbushings 33. These spiders have the multiplicity of radiating springfingers 34 provided with terminal rounded abutment portions, such as 35,which may be removably secured in position as by screws 36, thediametrical measurement from tip to tip of the members 35 preferablybeing slightly greater than the internal diameter of the work piece tobe mounted thereon.

As before, the thin tubular work piece or sleeve I3 is slipped over theholding device formed by this multiplicity of spring spiders, whichagain interiorly support the work piece with equal pressures presentedat a multiplicity of points. If desired, use may be made of a cap plateor abutment 31 adapted for intertting engagement with one terminus ofthe Work piece and centrally receiving the tensioning screw 38 engagedin socket 39 in the stud 32 for imparting an axial urge to the stud,tending to tension the individual spring fingers against lateraldeflection on application of opposed radial pressures thereto whichmight otherwise produce relative axial movement of the hub portion ofthe device with respect to the peripheral spring urged abutmentsinterfering with the eilicient reaction thereof.

By reference particularly to Figures 3 and 9, it will be noted thatadjacent sections or units which make up the work engaging member arepreferably disposed in opposite or staggered relation with respect toeach other whereby maximum circumferential distribution of the balancedwork supporting members is accomplished. It will be further noted thatas respects all forms of the invention illustrated, the basic structuralprinciples are the same and that in all instances the improved method offinishing tubular articles consists in uniformly supporting the articlein its initial form without distortion by engagement therewith or" amultiplicity of supporting devices, each individually urged intoengagement with the work piece yieldingly with a pressure insufficientto cause distortion of the work piece. It will be further noted that theprocess contemplates the maintenance of the members in work supporting`position by irictional resistance to their displacement, rather than byappreciable radial or axial pressures which might cause distortion sothat the work piece is properly universally supported and while sosupported is subjected to a tooling operation reacting on the surfaceopposite that so supported with a pressure below that which will causean axial displacement of the supporting members, permitting of radialdeection of the article, so that a true cylindrical or like surface maybe produced on the article which will remain true in contour g afterremoval of the work piece from its holding or supporting member. In thisconnection it is to be particularly noted that gage measurements showthat a work piece of the type here illustrated, in the absence of asupporting mechanism, may be grasped between the thumb and finger anddeiiected to cause as much as onetenth of an inch variation orelongation of diameter by such pressure but when supported by theimproved device of Figure 3, for example, will remain undefiected undermaximum pressure than can be applied by manual gripping thereof.

In Figure l there has been shown, as applied to the end sections, suchas ifi, a flexible annular ring 40 clamped in position as by the washer4l which in Figure l0 is shown as a'support securing member although, ifpreferred, the same could be made a part of the terminal discs 24 and25, for example. Both the member It and the member il are shown asformed with the cannelures or grooves l2 and 43 respectively of size toreceive the deflected peripheral exterior of the member iii as clearlyshown in Figure 10.

It will thus be understood that as the work piece I3 is slipped intoposition the members 40 at opposite ends of the holder will becorrespondingly deiiected, the one lying over into groove 42 while atthe opposite end the corresponding member will interiit with groove t3with the result that a tight seal is provided between the interior ofthe work piece and the exterior of the holder, eliminating thepossibility of grinding grit, chips or the like working into the holderand interfering with satisfactory operation of the individual yieldingwork engaging members.

It will, of course, be understood that by reversal of parts acorresponding sealing action may be effected in connection with theinternal chuck device shown in Figure 6.

What is claimed is:

1. An internal bracing member for support during machining of a Workpiece of iiexibility distortable by the necessary pressure of themachining operation, comprising a work piece supporting member having aplurality of pressure members supported for joint axial and radialmovement for engagement with the work piece, and means for individually,yieldingly urging said members into engagement with the work piece undera pressure insufficient to distort said work piece.

2. A device of the character described comprising a plurality of shorttubular sections each having a multiplicity of angularly disposed boresformed therein, laterally breaking through one of the cylindrical wallsof the section, work supporting members slidably mounted within saidbores, means for yeldingly actuating the supporting members in the boresin a direction to cause the supporting members to project beyond thewalls of the tubular members, and means for maintaining the tubularmembers in terminal intertting relation whereby a continuous tubularwork support is provided.

3. A device of the character described comprising :a plurality of shorttubular sections each having a multiplicity of angularly disposed boresformed therein, laterally breaking through one of the cylindrical wallsof the section, work supporting members slidably mounted within saidbores, means for yieldingly actuating the supporting members in thebores in a direction to cause the supporting members to project beyondthe walls of the tubular members, and means for maintaining the tubularmembers in terminal intertting relation whereby a continuous tubularwork support is provided, said yielding means comprising compressionsprings each terminally bearing at one end against one of the slidablework engaging members and at the other end against an adjacent tubularsection, substantially as and for the purpose described.

4. A work support for a iiexible tubular article comprising a mainsupporting member, a multiplicity of individual resiliently mountedcontact members disposed in longitudinally radially staggered relationand adapted for simultaneous engagement with one of the peripheral wallsof the tubular article, individual means for yieldingly urging therespective work engaging members against the Work with a non-distortingpressure, and means preventing relative axial movement of the mainsupport member and the Work piece.

5. A device of the character described comprising a body portion havinga multiplicity of separate individually actuable work engaging membersprojectable with respect to the body portion for engagement with a workpiece, and terminal exible sealing members carried by the body portionand projecting circumferentially with respect thereto in excess of thepotential projection of the work engaging members whereby said yieldableterminal devices will interlock with the supported face of a work pieceto prevent access of tooling produced chips to the Work supportingmembers. 6. A device of the character described comprising a bodyportion having a multiplicity of separate individually actuable workengaging members projectable with respect to the body portion forengagement with a work piece, and terminal flexible sealing memberscarried by the body portion and projecting circumferentially withrespect thereto in excess of the potential projection of the workengaging members whereby said yieldable terminal devices will interlockwith the supported face of a work piece to prevent access of toolingproduced chips to the work supporting members, said body portion beingformed with circumferential cannelures adjacent the flexible sealingmember permitting lateral iiexure of the sealing member substantially asand for the purpose described.

GEORGE W. BINNS. FREDERICK J.` THELER.

